When you want to migrate your email from old hosting provider into your new hosting provider, you can use imap-sync for this purpose.

II. Install imapsync

Run following command

sudo yum install epel-release
sudo yum install imapsync

II. Run imapsync to sync email

imapsync --host1 <source-host> --user1 <source-username> --passfile1 <source-password-file-path> --host2 <dest-host> --user2 <dest-username> --passfile2 <dest-password-file-path> --maxsize 100000000000  --maxlinelength 1000000